Display device and method of manufacturing the same

ABSTRACT

A display device includes a first substrate including a protrusion electrode pattern, a second substrate disposed opposite to the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate. The protrusion electrode pattern is made of a conductive polymer material, and a state of the liquid crystal layer changes from an isotropic state to an anisotropic state when an electric field is applied.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2008-0015963, filed on Feb. 21, 2008, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device.

2. Discussion of the Background

Several kinds of display devices exist. Due to rapid development ofsemiconductor technology, liquid crystal displays (LCDs) having improvedperformance and decreased size and weight have been developed.

In an LCD, light transmittance is determined by an alignment state of aliquid crystal layer. Because light transmittance is adjusted byphysical movement of the liquid crystal layer, the LCD may have aproblem in terms of response speed.

Blue phase liquid crystal that has a relatively fast response speed ofabout 3 μm has been developed. Because blue phase liquid crystal has avery narrow operating temperature range, a crystal structure thereof maybe stabilized by adding a monomer and polymerizing.

When an electric field does not exist, blue phase liquid crystal hasoptical isotropy, exhibits a blue phase, and does not havebirefringence. In this state, if an electric field is applied to theblue phase liquid crystal, it has optical anisotropy and birefringence.In this case, an electric field that is applied to the blue phase liquidcrystal is applied in a substantially horizontal direction. Here, thehorizontal direction indicates a direction parallel to a pair ofsubstrates that are disposed opposite to each other with blue phaseliquid crystal disposed therebetween. An electric field is applied tothe blue phase liquid crystal through an electrode in the substrate.

However, a display device using blue phase liquid crystal may have arelatively high driving voltage and deteriorated light transmittance.

Accordingly, by protruding an electrode from a substrate in a directionperpendicular to the substrate, a strong horizontal electric field,which is applied to the blue phase liquid crystal, may be formed,whereby the driving voltage may be lowered.

However, it may be difficult to stably protrude an electrode.Specifically, it may be difficult to accurately align the electrode whenforming the protruded electrode. If the electrode is not properlyaligned, the horizontal electric field may be weak, and therefore, thedriving voltage may not decrease even when the protruded electrode isused.

SUMMARY OF THE INVENTION

The present invention provides a display device having a deceaseddriving voltage.

The present invention also provides a method of manufacturing thedisplay device.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

The present invention discloses a display device including a firstsubstrate including a protrusion electrode pattern, a second substratedisposed opposite to the first substrate, and a liquid crystal layerdisposed between the first substrate and the second substrate. Theprotrusion electrode pattern is made of a conductive polymer material,and a state of the liquid crystal layer changes from an isotropic stateto an anisotropic state when an electric field is applied.

The present invention also discloses a method of manufacturing a displaydevice, including forming a thin film transistor on a substrate, coatinga conductive polymer layer on the substrate and the thin filmtransistor, and forming a protrusion electrode pattern that is connectedto the thin film transistor by imprinting the conductive polymer layer.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a layout view of a display device according to an exemplaryembodiment of the present invention.

FIG. 2 is a cross-sectional view of the display device taken along lineII-II of FIG. 1.

FIG. 3 is a diagram showing a process of stabilizing blue phase liquidcrystal included in the display device of FIG. 1.

FIG. 4 is a diagram showing changing characteristics according towhether an electric field is applied to blue phase liquid crystal thatis used for the display device of FIG. 1.

FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9, and FIG. 10 are cross-sectionalviews sequentially showing a process of manufacturing the display deviceof FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure isthorough, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the size and relative sizes oflayers and regions may be exaggerated for clarity. Like referencenumerals in the drawings denote like elements,

It will be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, it can bedirectly on or directly connected to the other element or layer, orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on” or “directly connected to”another element or layer, there are no intervening elements or layerspresent.

In an exemplary embodiment, a display device may include an amorphoussilicon (a-Si) thin film transistor (TFT) that is formed in a processusing five masks. Further, two TFTs may be used in one pixel. A pixel isa minimum unit for displaying an image. However, in exemplaryembodiments of the present invention, a TFT may be embodied in variousforms and is not limited to the example that is described herein.

An exemplary embodiment of the present invention is described withreference to FIG. 1 and FIG. 2. FIG. 1 is a layout view of a displaydevice 900 according to an exemplary embodiment of the presentinvention, and FIG. 2 is a cross-sectional view of the display devicetaken along line II-II of FIG. 1.

As shown in FIG. 1 and FIG. 2, the display device 900 includes a firstsubstrate 100, a second substrate 200, and a liquid crystal layer 300.

The first substrate 100 includes a first substrate member 110 and aprotrusion electrode pattern 180 disposed on the first substrate member110.

The protrusion electrode pattern 180 includes a first protrusionelectrode 181 and a second protrusion electrode 182 that are disposedapart from each other. The first protrusion electrode 181 and the secondprotrusion electrode 182 are formed in slit patterns so that they arealternately engaged with each other.

The first protrusion electrode 181 and the second protrusion electrode182 protrude toward the liquid crystal layer 300 in a directionperpendicular to the first substrate member 110. Therefore, a horizontalelectric field may be effectively formed between the first protrusionelectrode 181 and the second protrusion electrode 182. Here, thehorizontal electric field indicates a direction that is substantiallyparallel to the first substrate 100 and the second substrate 200 thatare disposed opposite each other with the liquid crystal layer 300disposed therebetween. This is because the first electrode 181 and thesecond electrode 182 each have a three-dimensional shape.

The width of each protrusion electrode pattern 180, i.e., the firstprotrusion electrode 181 and the second protrusion electrode 182, and adistance between the protrusion electrodes 181 and 182 is small, whichmay improve the performance of the display device 900. Further, as theheight of the protrusion electrode pattern 180 increases, the drivingvoltage decreases, but a minimum distance should be maintained betweenthe first substrate 100 and the second substrate 200 to obtain anappropriate transmittance of light.

In consideration of the above-described condition and an actual marginin a manufacturing process, each of the first protrusion electrode 181and the second protrusion electrode 182 of the protrusion electrodepattern 180 may have a width in the range of 1 μm to 10 μm and the firstprotrusion electrode 181 and the second protrusion electrode 182 may bedisposed at a distance in the range of 1 μm to 10 μm apart. Further, theprotrusion electrode pattern 180 may have a height in the range of 1 μmto 6 μm.

In addition, if a distance between the first protrusion electrode 181and the second protrusion electrode 182 is greater than the width ofeach of the first protrusion electrode 181 and the second protrusionelectrode 182, light transmittance may be improved, and if a distancebetween the first protrusion electrode 181 and the second protrusionelectrode 182 is smaller than the width of each of the first protrusionelectrode 181 and the second protrusion electrode 182, the drivingvoltage may be decreased. Because a display device 900 that uses bluephase liquid crystal may have a relatively high driving voltage, it maybe more advantageous to decrease the driving voltage. Therefore, thewidth of each of the first electrode 191 and the second electrode 192may be greater than or equal to a distance between the first electrode181 and the second electrode 182. However, the present invention is notlimited thereto. Therefore, when attempting to increase lighttransmittance, rather than decrease the driving voltage, the width ofeach of the first protrusion electrode 181 and the second protrusionelectrode 182 may be less than a distance between the first protrusionelectrode 181 and the second protrusion electrode 182.

Further, in FIG. 2, a cross-section of the first protrusion electrode181 and the second protrusion electrode 182 may have a quadrangularshape, but the present invention is not limited thereto. Therefore, across-section of the first protrusion electrode 181 and the secondprotrusion electrode 182 may be a polygonal shape, a semicircular shape,or a semi-oval shape instead of a quadrangular shape.

Further, the protrusion electrode pattern 180 may be made of aconductive polymer material. The conductive polymer material may be madeby mixing a conductive particle with an insulating or semiconductingpolymer, or by chemically processing an insulating or semiconductingpolymer.

Hereinafter, the conductive polymer material that is made by mixing aconductive particle with an insulating or semiconducting polymer isreferred to as a mixed conductive polymer material.

The mixed conductive polymer material indicates a polymer materialhaving conductivity due to conductive particles that are mixed with theinsulating or semiconducting polymer.

The mixed conductive polymer material is made by mixing conductiveparticles with a thermoplastic polymer material. In this case,particles, such as metal powder particles, carbon nanotubes (CNT),and/or carbon nanofiber (CNF), may be used as the conductive particles.

The mixed conductive polymer material may include a highly conductivepolyethylene-dioxythiophene (PEDOT).

Hereinafter, a conductive polymer material that is made by chemicallyprocessing an insulating or semiconducting polymer is referred to as apure conductive polymer material.

The pure conductive polymer material indicates a polymer material thathas conductivity due to chemical processing of an insulating orsemiconducting polymer.

The pure conductive polymer material may include polyacetylene that isprocessed with iodine. By processing polyacetylene having asemiconducting property with iodine, the polyacetylene has electricalconductivity similar to that of a metal.

The pure conductive polymer material may include polyaniline,polypyrrole, polythiophene, poly(p-phenylene), poly(p-phenylenevinylene), poly(3,4-ethylenedioxythiophene) (PEDOT), or poly(thienylenevinylene).

Such conductive polymer materials may have electrical conductivity in arange of 10⁻¹⁶ S/cm to 10⁵ S/cm.

Further, the first substrate 100 further includes TFTs 101 and 102, agate line 121, and data lines 161 a and 161 b that are disposed on thefirst substrate member 110.

The TFT includes the first TFT 101 and the second TFT 102. The first TFT101 is connected to the first protrusion electrode 181, and the secondTFT 102 is connected to the second protrusion electrode 182. The firstTFT 101 and the second TFT 102 are connected to the same gate line 121and to different data lines 161 a and 161 b. Accordingly, differentvoltages are applied to the first protrusion electrode 181 and thesecond protrusion electrode 182, and a horizontal electric field isgenerated between the first protrusion electrode 181 and the secondprotrusion electrode 182. The horizontal electric field is an electricfield that is generated in a direction substantially parallel to thesubstrates 100 and 200. Liquid crystal of the liquid crystal layer 300is moved by the horizontal electric field generated between the firstprotrusion electrode 181 and the second protrusion electrode 182.

Further, the first substrate 100 also includes a color filter 175. Thecolor filter 175 is disposed between the first substrate member 110 andthe protrusion electrode pattern 180. The color filter 175 gives a colorto light passing through the liquid crystal layer 300.

The second substrate 200 includes a second substrate member 210 and isdisposed opposite the first substrate 100.

The liquid crystal layer 300 includes crosslinked blue phase liquidcrystal and is disposed between the first substrate 100 and the secondsubstrate 200. The blue phase liquid crystal of the liquid crystal layer300 moves according to a horizontal electric field generated between thefirst protrusion electrode 181 and the second protrusion electrode 182.Because an operating temperature range of the blue phase liquid crystalis small, the blue phase liquid crystal is polymerized by adding anon-liquid crystalline monomer to low molecule liquid crystal that canexhibit a blue phase and applying ultraviolet rays to the monomer.Thereby, crosslinked blue phase liquid crystal having a stabilizedcrystal structure is manufactured. The crosslinked blue phase liquidcrystal has a form in which a net shape structure of a polymer is formedin a low molecule liquid crystal. That is, the blue phase liquid crystalis stabilized for a large temperature range by curing a monomer that isadded to chiral nematic liquid crystal in a polymer. The blue phase isone of liquid crystal phases that appear in several temperature rangesbetween a cholesteric phase and an isotropic phase.

When using the liquid crystal layer 300 including the blue phase liquidcrystal, it may be unnecessary to form an alignment layer on the firstsubstrate 100 and the second substrate 200. When an electric field doesnot exist, the blue phase liquid crystal has optical isotropy, exhibitsa blue phase, and does not have birefringence. In this state, if anelectric field is applied to the blue phase liquid crystal, the bluephase liquid crystal may have optical anisotropy and birefringence. Asthe intensity of an electric field increases, the number of directorsthat are arranged in the direction of the electric field increases, sothe blue phase liquid crystal has refractive anisotropy and thus itsinput polarization state changes. That is, transmittance may be adjustedwhen the alignment of the blue liquid crystal of the liquid crystallayer 300 changes according to a horizontal electric field (transverseelectric field) that is formed between the first protrusion electrode181 and the second protrusion electrode 182.

Further, when an electric field does not exist, because the blue phaseliquid crystal has optical isotropy, the display device 900 drives in anormally black mode. That is, the display device 900 displays black whena voltage is not applied to the electrodes 181 and 182.

A non-liquid crystalline monomer is a material that is polymerized byheat or ultraviolet rays. As the non-liquid crystalline monomer, anacrylate-based monomer may be used, but the non-liquid crystallinemonomer is not limited thereto. As the non-liquid crystalline monomer, amonomer including a polymerization radical such as a vinyl radical, anacryloyl radical, or a fumarate radical may be used. An initiator thatcan initiate polymerization of a cross-linker and a monomer may be used,as needed. As an initiator, acetophenone, benzophenone, etc., may beused. Further, it may be possible to add a chiral dopant to exhibit achiral nematic phase to the liquid crystal layer 300.

A material that can exhibit a blue phase between a cholesteric phase(chiral nematic phase) and an isotropic phase may be used as the lowmolecule liquid crystal. Such a low molecule liquid crystal may includea molecular structure such as biphenyl and cyclohexyl, and may include amaterial that has chirality or a material that can exhibit a cholestericphase when a chiral dopant is added.

Referring to FIG. 3 and FIG. 4, the blue phase liquid crystal that isused for the display device 900 according to an exemplary embodiment ofthe present invention is additionally described.

As shown in FIG. 3, the blue phase liquid crystal may be made by forminga light curable polymer when deriving a chiral phase to positive liquidcrystal and forming a blue phase at about 1 K (absolute temperature).Such blue phase liquid crystal is stable at temperatures up to roomtemperature.

Because a blue phase that is stabilized for a large temperature range bya polymer has a good equilibrium constant (K), a gray can be expressedby applying an electric field, and when an electric field does notexist, the blue phase has optical isotropy.

As shown in FIG. 4, when an electric field does not exist, blue phaseliquid crystal has optical isotropy, exhibits a blue phase, and does nothave birefringence. In this state, if an electric field is applied tothe blue phase liquid crystal, the blue phase liquid crystal has opticalisotropy and birefringence. In this case, an electric field that isapplied to the blue phase liquid crystal is applied in a horizontaldirection, i.e., a direction that crosses a direction in which lightpasses through the liquid crystal layer 300.

Further, the blue phase liquid crystal that is used for the displaydevice according to an exemplary embodiment of the present invention mayhave a chiral pitch of 300 nm or less, for example, about 200 nm. Thisis because the chiral pitch of the blue phase liquid crystal should notoverlap with a wavelength region of visible rays. Because the wavelengtharea of visible rays is in the range of about 350 nm to 650 nm, the bluephase liquid crystal should have a chiral pitch of 300 nm or less.

Further, the blue phase liquid crystal may have very high permittivityand refractive index, and has a nematic state.

Referring to FIG. 2, a structure of the display device 900 is describedbelow in detail. FIG. 2 shows the first TFT 101. Hereinafter, a TFTactually indicates the first TFT 101, but the second TFT 102 has astructure that is substantially identical to that of the first TFT 101.

First, a structure of the first substrate 100 will be described.

The first substrate member 110 may include a material such as glass,quartz, ceramic, or plastic, and is transparently formed.

A plurality of gate lines 121 (see FIG. 1), a plurality of gateelectrodes 124 branched from the gate lines 121, and a plurality ofstorage electrode lines 128 are disposed on the first substrate member110.

The gate wires 121, 124, and 128 may be made of a metal such as Al, Ag,Cr, Ti, Ta, Mo, and Cu, or alloys including the metal. In FIG. 2,although the gate wires 121, 124, and 128 are shown in a single layer,the gate wires 121, 124, and 128 may include multiple layers. The gatewires 121, 124, and 128 may include a metal layer of Cr, Mo, Ti, and/orTa, which are excellent in physical and chemical characteristics, oralloys including the same, or an Al-based or Ag-based metal layer havinglow resistivity. The gate wires 121, 124, and 128 may be made of variousmetals or conductors, and may be made of a multilayer that can bepatterned under the same etching conditions.

The gate insulating layer 130, which may be made of silicon nitride(SiN_(x)), is disposed on the gate wires 121, 124, and 128.

A data wire including a plurality of data lines 161 a and 161 b (seeFIG. 1) crossing the gate line 121, a plurality of source electrodes 165branched from the data lines 161 a and 161 b, and a plurality of drainelectrodes 166 spaced apart from the source electrode 165 is disposed onthe gate insulating layer 130.

Like the gate wires 121, 124, and 128, the data wires 161 a, 161 b, 165,and 166 may be made of a conductive material such as chromium,molybdenum, aluminum, copper, or alloys including the same, and may be asingle layer or multiple layers.

A semiconductor layer 140 is disposed in a region including an upperpart of a gate insulating layer 130 on the gate electrode 124 and alower part of the source electrode 165 and the drain electrode 166.Specifically, at least a part of the semiconductor layer 140 overlapswith the gate electrode 124, the source electrode 165, and the drainelectrode 166. The gate electrode 124, the source electrode 165, and thedrain electrode 166 are three electrodes of the TFT 101. Thesemiconductor layer 140 between the source electrode 165 and the drainelectrode 166 becomes a channel region of the TFT 101.

Further, ohmic contacts 155 and 156 to reduce contact resistance aredisposed between the semiconductor layer 140 and each of the sourceelectrode 165 and the drain electrode 166. The ohmic contacts 155 and156 may be made of amorphous silicon in which silicide or an n-typeimpurity is doped in a high concentration.

A passivation layer 170, which may be made of an inorganic insulatingmaterial such as silicon nitride or silicon oxide, an organic insulatingmaterial, or a low dielectric constant insulating material such asa-Si:C:O and a-Si:O:F that is formed by plasma enhanced chemical vapordeposition (PECVD), may be disposed on the data wires 161 a, 161 b, 165,and 166.

Color filters 175 having three primary colors may be sequentiallydisposed on the passivation layer 170. In this case, colors of the colorfilters 175 are not limited to three primary colors and may variously beformed in at least one color. The color filters 175 give a color tolight that passes through the display device 900.

The color filter 175 is disposed on the passivation layer 170, but thepresent invention is not always limited thereto. Therefore, the colorfilter 175 may be formed between the passivation layer 170 and the datawires 161 a, 161 b, 165, and 166. Further, the color filter 175 may bedisposed on the second substrate 200 rather than the first substrate100.

Further, a light blocking member 176 is disposed on a portion of thepassivation layer 170 corresponding to the TFT 101 and on which thecolor filter 175 is not disposed. The light blocking member 176suppresses an operation error of the TFT 101 due to generation of alight leakage current when light enters a channel region of the TFT 101.The light blocking member 176 is not always necessary and may be omittedas needed.

A capping layer 179 is disposed on the color filter 175 and the lightblocking member 176. The capping layer 179 protects organic layersincluding the color filter 175. The capping layer 179 is not alwaysnecessary and may be omitted as needed. The capping layer 179 may bemade of various materials, such as an inorganic layer including amaterial similar to that of the passivation layer 170.

A protrusion electrode pattern 180 is disposed on the capping layer 179.The protrusion electrode pattern 180 may be made of a conductive polymermaterial through an imprinting process.

The protrusion electrode pattern 180 includes a first protrusionelectrode 181 and a second protrusion electrode 182. The firstprotrusion electrode 181 is connected to the first TFT 101, and thesecond protrusion electrode 182 is connected to the second TFT 102 (seeFIG. 1). Specifically, the first protrusion electrode 181 and the secondprotrusion electrode 182 include a protruding electrode 1812 and aconnection part 1811 that connects the protruding electrode 1812 and theTFT 101.

Further, a part 1815 of the protrusion electrode pattern 180 overlaps afirst storage electrode line 128 of a gate wire to secure storagecapacity.

Further, the passivation layer 170 and the capping layer 179 have aplurality of contact holes 171 and 172 that expose a portion of thedrain electrode 166 of the first TFT 101 and the second TFT 102,respectively. In certain cases, the color filter 175 may also havecontact holes 171 and 172 together with the passivation layer 170 andthe capping layer 179. The first protrusion electrode 181 and the secondprotrusion electrode 182 are connected to the drain electrodes 166 ofthe first TFT 101 and the second TFT 102 through the contact holes 171and 172, respectively. Further, the color filter 175 further includes anopening 174 formed on the first storage electrode line 128.

Blue phase liquid crystal of the liquid crystal layer 300 has anarrangement state that changes according to a horizontal electric fieldthat is generated between the first protrusion electrode 181 and thesecond protrusion electrode 182, whereby light transmittance may beadjusted.

Next, the second substrate 200 includes a second substrate member 210will be described.

Like the first substrate member 110, the second substrate member 210 mayinclude a material such as glass, quartz, ceramic, or plastic, and istransparent.

However, in order to reduce the weight and thickness thereof, the secondsubstrate member 210 may be made of plastic. The plastic may bepolycarbonate, polyimide, polyethersulfone (PES), polyallylate (PAR),polyethylenenaphthalate (PEN), or polyethyleneterephthalte (PET), but isnot limited thereto.

The display device 900 according to an exemplary embodiment of thepresent invention has a protrusion electrode that is accurately formedwhile having a simple structure, whereby the driving voltage thereof maybe stably decreased.

A method of manufacturing a display device 900 according to an exemplaryembodiment of the present invention is described hereinafter withreference to FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, and FIG.11.

First, as shown in FIG. 5, the TFT 101 including the gate electrode 124,the semiconductor layer 140, the ohmic contacts 155 and 156, the drainelectrode 166, and the source electrode 165, and the passivation layer170 that covers the TFT 101 are formed. A structure of the TFT 101 isnot limited to the structure that is shown in the accompanying drawings,and the TFT 101 may have any of various structures. Further, the storageelectrode line 128 may be formed simultaneously with the gate electrode124 on the same layer and with the same material as that of the gateelectrode 124.

Next, as shown in FIG. 6, the color filter 175 is formed on thepassivation layer 170. The color filter 175 has an opening 174corresponding to the storage electrode line 128.

As shown in FIG. 7, the TFT 101 is covered by forming the light blockingmember 176.

As shown in FIG. 8, after the capping layer 179 that covers the colorfilter 175 and the light blocking member 176 is formed, a contact hole171 that exposes the drain electrode 166 of the TFT 101 is formedthrough a photolithography process.

Next, as shown in FIG. 9, a conductive polymer layer 800 is coated onthe capping layer 179. The conductive polymer layer 800 is made bymixing conductive particles with an insulating or semiconducting polymeror by chemically processing an insulating or semiconducting polymer.Specifically, for example, the conductive polymer layer may be made of ahighly conductive polyethylene-dioxythiophene (PEDOT), or may be made bychemically processing at least one of polyacetylene, polyaniline,polypyrrole, polythiophene, poly(p-phenylene), poly(p-phenylenevinylene), poly(3,4-ethylenedioxythiophene) (PEDOT), or poly(thienylenevinylene).

As shown in FIG. 10, the conductive polymer layer 800 is then imprintedusing a mold 850 in which a depression pattern 851 is formed. Thedepression pattern 851 has a shape corresponding to the protrusionelectrode pattern 180 to form with the conductive polymer layer 800.Therefore, when the mold 850 is removed after imprinting, the protrusionelectrode pattern 180 is formed.

The protrusion electrode pattern 180 includes a first protrusionelectrode 181 and a second protrusion electrode 182. The firstprotrusion electrode 181 and the second protrusion electrode 182 areconnected to the first TFT 101 and the second TFT 102 through thecontact holes 171 and 172, respectively.

Each of the first protrusion electrode 181 and the second protrusionelectrode 182 may have a width in the range of 1 μm to 10 μm, and thefirst protrusion electrode 181 and the second protrusion electrode 182may be disposed at a distance in the range of 1 μm to 10 μmtherebetween. Further, the protrusion electrode pattern 180 may have aheight in the range of 1 μm to 6 μm.

In addition, although not shown, an etching process that removes theremaining layer after imprinting may be further included. By removingthe remaining layer through the etching process, the first protrusionelectrode 181 and the second protrusion electrode 182 may be preventedfrom being connected by the remaining layer, and the conductive polymerlayer 800 remaining in an unnecessary portion is removed.

By such a manufacturing method, a protrusion electrode pattern, whichmay be made of a conductive polymer material, may be easily andaccurately formed.

According to exemplary embodiments of the present invention, as thedisplay device has a protrusion electrode that has a simple structureand is accurately formed, the driving voltage may be stably decreased.

Further, a method of manufacturing a display device in which aprotrusion electrode may easily be formed may be provided.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A display device, comprising: a first substrate comprising aprotrusion electrode pattern; a second substrate disposed opposite thefirst substrate; and a liquid crystal layer disposed between the firstsubstrate and the second substrate, wherein the protrusion electrodepattern comprises a conductive polymer material, and a state of theliquid crystal layer changes from an isotropic state to an anisotropicstate when an electric field is applied.
 2. The display device of claim1, wherein the conductive polymer material comprises: a conductiveparticle; and an insulating polymer or a semiconducting polymer.
 3. Thedisplay device of claim 1, wherein the conductive polymer materialcomprises either a chemically processed insulating polymer or achemically processed semiconducting polymer.
 4. The display device ofclaim 1, wherein the protrusion electrode pattern comprises a firstprotrusion electrode and a second protrusion electrode disposed apartfrom each other, and the first protrusion electrode and the secondprotrusion electrode have slit patterns that are alternately engagedwith each other.
 5. The display device of claim 4, wherein the firstsubstrate comprises: gate lines; data lines; a first thin filmtransistor (TFT) connected to the first protrusion electrode; and asecond TFT connected to the second protrusion electrode, wherein thefirst TFT and the second TFT are connected to the same gate line and todifferent data lines.
 6. The display device of claim 4, wherein liquidcrystal of the liquid crystal layer is moved by an electric fieldgenerated between the first protrusion electrode and the secondprotrusion electrode, and the electric field is a horizontal electricfield substantially parallel to the first substrate and the secondsubstrate.
 7. The display device of claim 4, wherein each of the firstprotrusion electrode and the second protrusion electrode has a width inthe range of 1 μm to 10 μm, and the first protrusion electrode and thesecond protrusion electrode are disposed at a distance in the range of 1μm to 10 μm from each other.
 8. The display device of claim 1, whereinthe protrusion electrode pattern has a height in the range of 1 μm to 6μm.
 9. A method of manufacturing a display device, comprising: forming athin film transistor (TFT) on a substrate; coating a conductive polymerlayer on the substrate and the TFT; and forming a protrusion electrodepattern that is connected to the TFT by imprinting the conductivepolymer layer.
 10. The method of claim 9, wherein a mold in which adepression pattern corresponding to the protrusion electrode pattern isformed is used to imprint the conductive polymer layer.
 11. The methodof claim 9, wherein forming the protrusion electrode pattern furthercomprises an etching process that removes a portion of the conductivepolymer layer that is not part of the protrusion electrode pattern afterimprinting.
 12. The method of claim 9, further comprising mixing aconductive particle with either an insulating polymer or asemiconducting polymer to form the conductive polymer layer.
 13. Themethod of claim 9, wherein the conductive polymer layer comprises eithera chemically processed insulating polymer or a chemically processedsemiconducting polymer.
 14. The method of claim 9, wherein the TFTcomprises a first TFT and a second TFT, the protrusion electrode patterncomprises a first protrusion electrode connected to the first TFT and asecond protrusion electrode connected to the second TFT and spaced apartfrom the first protrusion electrode, and the first protrusion electrodeand the second protrusion electrode having slit patterns that arealternately engaged with each other.
 15. The method of claim 14, whereineach of the first protrusion electrode and the second protrusionelectrode has a width in the range of 1 μm to 10 μm, and the firstprotrusion electrode and the second protrusion electrode are disposed ata distance in the range of 1 μm to 10 μm from each other.
 16. The methodof claim 9, wherein the protrusion electrode pattern has a height in therange of 1 μm to 6 μm.
 17. The method of claim 9, further comprisingforming a color filter between the substrate and the protrusionelectrode pattern.
 18. The display device of claim 2, wherein theconductive particle comprises a metal powder particle, a carbon nanotube(CNT), or carbon nanofiber (CNF).
 19. The display device of claim 1,wherein the liquid crystal layer has a chiral pitch of 300 nm or less.20. The display device of claim 19, wherein the liquid crystal layer hasa chiral pitch of 200 nm.